Abrasive tool having safe and active areas

ABSTRACT

A tool for abrading a workpiece to smooth the surface thereof. In one embodiment, the tool is an ultrasonic tip ( 12 ) having plural grooves ( 16 ) formed in a smooth surface ( 14 ) thereof. Each groove ( 16 ) includes an abrasive material ( 24 ) coating the depression thereof. Rough surface areas of a workpiece projecting into the groove ( 16 ) are abraded to thereby result in a smooth workpiece surface. Once the surface roughness of the workpiece has been removed, the smooth areas ( 14 ) of the ultrasonic tip ( 12 ) are engaged, thereby preventing further abrasion of the workpiece.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Application claims the benefit of pending Provisional PatentApplication entitled “ULTRASONIC ACTIVATED SCALING TIP,” filed Mar. 26,1999, and bearing Ser. No. 60/126,474, the entire disclosure of which isincorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to tools that are moveable onwork surfaces to perform operations thereon, and more particularly totools of the type having safe areas and active areas to remove roughsurface areas and provide a smooth surface.

BACKGROUND OF THE INVENTION

Tools are utilized by many different crafts persons for working onvarious types of materials to fabricate an object with the desired shapeor form. While the majority of tools are utilized by machinists andother crafts persons working in similar trades, various types of toolsare also utilized on a daily basis by artists, carpenters, cabinetmakers, engineers, physicians, dentists, etc. Depending on theapplication to which the tool is applied, the particular devices may bemoved by hand, rotated, reciprocated or otherwise vibrated to operateupon the surface of the workpiece.

In many applications, there is a need to smooth an otherwise roughworkpiece surface. Hand files, sanders, shapers, planers, etc., are welladapted for creating a smooth workpiece surface. While these and othertools are well adapted for carrying out this function, the operation ofsuch type of tools requires a certain degree of skill to prevent anexcessive amount of material from being removed from the workpiece toprepare a smooth surface. In other words, in utilizing many of thesesmoothing-type tools, the operator must be careful to halt the operationonce the surface is smooth, otherwise, the continued operation of theequipment will only unnecessarily remove further material from theworkpiece.

In the dental field, doctors routinely utilize ultrasonic scalers toremove brittle calculus, tartar, altered cementum and other accumulatedresidue from a patient's tooth. During supragingival scaling or rootplaning, the material to be removed is universally rough with multiplejagged and protruding edges. The buildup on the enamel of a tooth isundesirable which, if not removed, can be damaging to the tooth andgingival tissue. The ultrasonic scaler is equipped with a tip whichmechanically vibrates at a high frequency. When brought into contactwith the hardened residue, the brittle material is fractured and erodedand removed from the tooth. The end of the metal tip of the ultrasonicscaler insert fractures and breaks the brittle buildup with amicro-hammer action. This method of removing calculus from a patient'stooth is well documented in the dental literature. In order tofacilitate the removal of calculus and other materials formed over timeon a patient's tooth, the ultrasonic tip can be coated with diamondparticles, such as disclosed in U.S. Pat. No. 4,731,019 by Martini. Thediamond particles covering the ultrasonic scaler tip function toaccelerate the abrasion of the brittle calculus. Indeed, an extremeamount of care must be exercised by the doctor in the utilization ofthis tool, otherwise, the surface of the tooth will be abraded anddamaged. It can be appreciated that the doctor or assistant must be veryattentive when utilizing this ultrasonic tool, otherwise, the tooth,bone or other hard surface will be damaged beyond repair. It will alsobe appreciated that when the tip of this tool is utilized on that partof the tooth in the gingival pocket, excessive tooth abrasion can occurbecause the surgeon is unable to visually observe the tooth surfacebeing operated upon. As a result, diamond coated ultrasonic tips havebeen limited to a small specialty area of dentistry by experienceddoctors, namely, the periodontal surgical area.

Ultrasonic operated devices utilize tips that are constructed ofspecified lengths so as to be tuned A tuned tip provides optimummagnitude vibrations and thus is effective to micro-hammer objectsurfaces. Standard ultrasonic tips are effective only along about 4-6 mmat the end of the tip to remove accretions on a tooth surface. The otherportion of the ultrasonic tip is less effective as an instrument toremove calculus and tartar buildup on tooth surfaces.

It is well known in the art to bond diamond particles to tool bits, andthe like, in order to accelerate abrasion of the workpiece and extendthe life of the tool. Diamond whetstones are such type of tools. Thesetools are fabricated by bonding a diamond abrasive in raised islands onthe surface of the tool. The raised islands of diamond particles areeffective to erode the surface of the workpiece. Again, the surface ofthe workpiece continues to be eroded as long as the operator moves thewhetstone over the surface of the workpiece.

As noted above, ultrasonic scaler tips that are covered with a diamondabrasive grit currently exist. Abrasive or sharp edges on the surface ofa scaler tip have been shown to be an effective means of removing tartarand roughness from the tooth surface. However, studies have demonstratedthat abrasive areas and sharp edges, when vibrated by an ultrasonicscaler and placed directly against the tooth surface, will damage thesurfaces of the tooth and root. In other words, not only the calculus,tartar, and other unwanted rough surfaces will be removed as desired,but a significant portion of the tooth surface will also be removed,thus causing permanent damage to the tooth.

From the foregoing, it can be seen that a need exists for a tool thatremoves roughened areas of a workpiece surface, but once a smoothsurface is achieved, further erosion of the surface does not occur, evenif the tool continues to be moved over the work surface. Another needexists for a tool that can be used by a technician to smooth surfaces ofworkpieces without utilizing a high degree of skill. Another need existsfor an ultrasonic tip which, when used on tooth surface that cannot beeasily observed, does not continue to erode the surface of a tooth oncea smooth surface is achieved.

SUMMARY OF THE INVENTION

In accordance with the principles and concepts of the invention, thereis provided a tool with safe and active areas that overcome thedisadvantages attendant with the known prior art tools. In oneembodiment, there is provided a tool for removing rough areas from aworkpiece until the workpiece is smooth. The tool includes a safe areawhich, when engaged with the workpiece, does not erode or abrade thesurface of the workpiece. The tool also includes an active area formedas a depression in the safe area. The active area has formed therein anabrasive mechanism for abrading rough areas of the workpiece thatprotrude therein. In one feature of the invention, once the active areafunctions to remove the rough areas of the workpiece, it no longerengages the workpiece surface, whereupon the safe area of the tool comesinto contact with the smooth workpiece and further removal of theworkpiece material is prevented.

In a preferred embodiment of the invention, a scaling tip is fitted intoor attached to various forms of ultrasonic transducers utilized in theremoval of calculus and roughness from teeth and other hard tissues. Insuch ultrasonic instruments, the ultrasonic energy can be transmittedfrom a generator of ultrasonic energy, such as a magnetostrictive pileor a piezoelectric element, to metal scaler tips of various standardshapes to access different areas of the tooth surface. The metal scalertips may additionally be smooth or may contain grooves or ridges tochannel coolant water to the end of the scaler tip.

In accordance with the invention, a scaler tip which can be of variousshapes, includes a metal tip having one or more shallow depressions onthe portion of the tip that contacts the tooth surface. Within thesedepressions is an active surface that has formed an abrasive or cuttingsurface. This active surface may include either a coating of abrasivematerial such as diamond grit, or a sharpened edge of the metal of thescaler tip. The diamond grit or sharpened edge does not extend above thesmooth safe areas of the scaler tip. By limiting the areas covered byabrasive, the scaler tip of the invention is safe for use on the toothsurface and does not excessively erode the tooth surface. The metalportion of the scaler tip that comes in contact with the tooth surfacehas a smooth surface and rounded edges, in the same manner as mostexisting scaler tips. Additionally, the smooth surface of the scaler tipwill effectively protect the tooth and root surfaces from the abrasiveor sharpened edges that are located in the shallow depressions formed inthe smooth metal surface. However, rough uneven accretions of tartar orother roughness on the tooth surface will project into the shallowdepressions and come in contact with the abrasive or sharp edges in theshallow grooves. The rough uneven material on the tooth will thus berapidly removed by the abrasive or sharpened edges, thereby leaving asmooth surface. Thereafter, only the smooth, non-abrasive metal surfaceof the scaler will come in contact with the tooth surface. The overallresult of this action is that a more rapid removal of accumulations androughness from the tooth and root surfaces is achieved, as compared toconventional scaler tips, without undesirable damage to the tooth androot surfaces. Additionally, after the major portion of the accretionshas been removed, the same scaler tip can be used to finish smoothingthe tooth surface without damage. Again, this results in a more rapidtartar removal without damage to the tooth. Both speed and safety forthe operator and the patient is achieved.

In accordance with a preferred method of the invention, when theactive/passive scaler tip is brought against the tooth surface to becleaned, the active surface bears on the protruding projections of thetartar or calculus that is to be removed. As this unwanted material isremoved, the smooth rounded surface of the tooth is encountered. Thesmooth surface of the tooth does not extend into the shallow depressionsof the ultrasonic tip and will therefore not encounter the activesurfaces formed in the depressions. Rather, the only surface of thescaler tip that will touch the root surface will be the smooth polishedmetal of the main body of scaler tip and the rounded polished edges ofthe shallow depressions. These polished surfaces will then function in amanner similar to currently available (smooth surface) scaler tips andcan be used to perform the final smoothing of the tooth surface withoutscratching or damaging.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings in which furtherfeatures and advantages will become apparent from the following and moreparticular description of the preferred and other embodiments of theinvention, as illustrated in the accompanying drawings in which likereference characters generally refer to the same parts or elementsthroughout the views, and in which:

FIG. 1 illustrates an ultrasonic insert with a smooth metal scaler tiphaving formed therein linear depressions or grooves coated with anabrasive material;

FIG. 2 is a cross-sectional view of the scaler tip of FIG. 1 taken alongline 2—2, which illustrates the smooth metal surface of the scaler tip,the rounded edges of the depressions, and an abrasive coating formed onthe surface of each depression;

FIG. 3 is a cross-sectional view of yet another embodiment, in which thesmooth metal of the scaler tip is shown with depressions therein, andwith a sharpened edge of metal recessed from the smooth surface,

FIG. 4 illustrates another embodiment of an ultrasonic insert with asmooth metal ultrasonic scaler tip having formed therein multipleisolated depressions, each coated with an abrasive material;

FIG. 5 illustrates a side view of yet another embodiment of theinvention in which the ultrasonic scaler tip is tubular in form, withone or more windows cut therein, and where the edges of the window aresmooth on the outside and sharp on the inside; and

FIG. 6 is a cross-sectional view of the scaler tip of FIG. 5, takenalong line 6—6 thereof

DETAILED DESCRIPTION OF THE INVENTION

While the tool constructed according to the invention is described belowin connection with an ultrasonic tip utilized in periodontal operations,the principles and concepts can be employed on tools that are applicablefor use in many other areas and trades. Also, while the operation of theultrasonic tool described below is in conjunction with movement by wayof ultrasonic vibrations, tools constructed in accordance with theinvention can also be moved on the workpiece by other mechanisms, suchas rotary, circular, reciprocatory, hand moved, or any other action bywhich one or the other of the tool or the workpiece is moved withrespect to the other. Tools that vibrate at frequencies other thanultrasonic, such as vibrations in the sonic frequency range, can employthe principles and concepts of the invention.

FIG. 1 illustrates a preferred form of an ultrasonic insert 8,comprising a metal scaler tip 12 constructed similar to those that areroutinely attached to ultrasonic generators for the purpose of removingroughness from the supra and sub gingival portions of a patient's teeth.Ultrasonic scaler tips 12 are typically constructed of a stainless steelor titanium material. The scaler tip 12 is mounted in a plastic holder10 that functions as a mount for the scaler tip 12 and the ultrasonicgenerator or transducer (not shown). The scaler tip 12 is constructedwith a smooth metal surface 14 that will not abrade or otherwise damagethe surface of the tooth. Within the smooth surface 14 of the metal tip12 are formed a number of linear depressions or grooves 16. The widthand depth of the grooves are a function of the roughness of the surfacematerial to be removed from the workpiece. For removing calculus andtartar of average buildup, the depth of each groove can be in the rangeof about 0.06-0.5 mm, and the width of each groove can be in the rangeof about 0.33-1.0 mm. The grooves are preferably milled in the hardmaterial of the ultrasonic tip 12, but can be formed by other means. Thetwo elongated edges of each depression 16 are rounded so as to notcreate a sharp edge of metal that might damage or erode the toothsurface. The edges of each groove 16 are made blunt or rounded by theuse of an end mill with rounded shoulders, or by using the well-knowntechnique of electric discharge machining. Beyond the rounded edge ofsmooth metal, the grooved depressions 16 are coated with an abrasivematerial such as diamond grit. In practice, a medium diamond grit issuitable for removing tartar and calculus from a tooth surface. Thediamond grit is bonded in the depressions of the grooves 16 by standarddiamond grit bonding techniques. Roughness on the tooth surface, such astartar or calculus, will enter the depressions and be abraded by theabrasive coating. Once the tartar or calculus is removed, the abrasivecoating will not come into contact with the smooth tooth surface,thereby preventing damage, wear, and abrasion of the smooth toothsurface.

FIG. 2 is an enlarged cross-sectional view of the scaler tip 12, takenalong line 2—2 of FIG. 1. The groove depressions 16 are shown formedbetween the smooth metal surface portions 14 of the scaler tip 12. Therounded edges 28 of each depression 16 are shown. The edges 28 arerounded to an extent where substantially no abrasion occurs when theedges 28 contact either roughened or smooth surfaces of a tooth. Theabrasive coating 24 is bonded on the trough portion of each depression16. It should be noted that the abrasive coating 24 does not extend tothe rounded edges 28 of the depression 16, thereby preventing theabrasive 24 from coming into contact with the tooth surface. The roughand protruding accretions of the calculus and tartar buildup projectinto the depression 16 and contact the abrasive coating 24. The roughaccretions are thus rapidly removed. In practice, many more abrasivecoated depressions 16 than shown can be formed around the ultrasonicscaler tip 12. Because the depth of the depressions 16 is a function ofthe contour of the tooth, the depressions can be formed around theultrasonic tip 12 with different depths. Alternatively, for highlycontoured tooth surfaces, a different ultrasonic tip can be employedthat has depressions with smaller openings in the smooth metal surface.

FIG. 3 illustrates an alternate embodiment of the scaler tip of theinvention, with one portion of the scaler tip shown enlarged. In thisembodiment, the depressions are shown as reference numeral 26, and arelocated between the smooth outer surfaces 14 of the ultrasonic scalertip. Located below the rounded edge 28 of each depression 26 is asharpened metal edge 38. In this embodiment, the smooth metal 14 of thescaler tip comes into contact with the tooth surface. Any tooth surfaceroughness, such as calculus or tartar, will come into contact with thesharpened metal edge 38 and will be rapidly removed. Those skilled inthe art may also choose to coat the depressions 26 with an abrasivematerial to facilitate erosion of rough surfaces that project therein.The sharpened edge 38 can quickly remove tartar projections, and theabrasive coating on the depressions 26 can complete smoothing of thetooth surface.

FIG. 4 shows a scaler tip 13 constructed according to another embodimentof the invention. Multiple small depressions 22 are formed in the smoothmetal surface of the scaler tip 13. The edges of the small depressionsare again made smooth so as not to damage the tooth surface. An abrasivecoating lines the depressions and functions in the same manner asdescribed in FIG. I above. The depressions 22 are also formed and coatedwith an abrasive in the same manner as described above.

FIGS. 5 and 6 show yet another embodiment of the invention providing anultrasonic scaler tip 44 formed as a tubular member 46. One or morewindows 48 are cut into the tubular portion 46 of the scaler tip 44. Theoutside edge 50 of the window 48 that contacts the tooth surface issmooth and rounded so as to not cause damage or abrasion to the toothsurface. The inside edge 52 of the window 48 is sharpened in such amanner as to act on any roughness such as calculus or tartar thatprojects into the window 48 of the scaler tip 46. Preferably, thetubular member 46 is constructed of a rigid material, such as stainlesssteel or titanium, and has an outside diameter in the range of about 1-2mm, and a sidewall thickness in the range of about 0 10-0.25 mm. Thewindow 48 can have an arcuate opening in the sidewall the size of about6-10 degrees, or other suitable size to accommodate the surfaceroughness and contour of the workpiece. The arcuate opening of thewindow 48 has a size that is also a function of the curvature of theworkpiece. To that end, the tubular member 46 can have different sizewindows 48 formed therearound to accommodate different workpiece surfaceshapes.

In the foregoing description of the various embodiments, the smoothsurfaces of the scaler tip that are not effective to substantiallyabrade the tooth are considered as “safe” areas, whereas theabrasive-coated areas and the sharp abrading edges are considered as“active” areas. When utilized with ultrasonic devices, the tool can bevibrated in both the subsonic and ultrasonic frequency ranges. Also,while a diamond grit abrasive is utilized in the preferred form of theinvention, other grits, such as corundum and others can be utilized withsuitable effectiveness.

Other combinations of the foregoing features will be evident to thoseskilled in the art. Many forms of smooth metal scaler tips containingdepressions with active cutting or abrading elements can be used. In allof these embodiments, the principle is to allow the smooth metal surfaceof the scaler tip to come in contact with the workpiece, while roughaccretions on the workpiece surface are acted upon by the active cuttingor abrading elements. The combination of these features will rapidlyremove the rough accretions from the workpiece surface while preventingdamage after the removal of the accretions by only allowing the smoothmetal surface to contact the workpiece. Indeed, those skilled in the artcould use many depressions aligned around the tool. In practice, it hasbeen found that the tool of the invention can be operated at a low powerlevel, as compared to corresponding prior art tools.

While the preferred embodiment of the method and apparatus has beendisclosed with reference to specific ultrasonic tips, it is to beunderstood that many changes in detail may be made as a matter ofengineering choices without departing from the scope of the invention asdefined by the appended claims. Indeed, those skilled in the art mayprefer to embody the apparatus in other forms, and in light of thepresent description they will find it easy to implement that choice.Also, it is not necessary to adopt all of the various advantageousfeatures of the present disclosure into a single composite tool in orderto realize the individual advantage.

What is claimed is:
 1. A tool for abrading raised portions from aworkpiece in response to relative movement between said tool and theworkpiece, comprising: an ultrasonic tip defining said tool a rigid andnonpliable material from which said ultrasonic tip is constructed; aworking area of said ultrasonic tip adapted for engaging the workpiece,said working area having a safe area and an active area; the safe areaof said ultrasonic tip defined by at least two spaced apart surfaceregions, each said surface region being a nonabrasive surface of saidworking area adapted for preventing abrasion of the workpiece whenengaged therewith; and the active area including one or more depressionsformed in said ultrasonic tip below a line tangent to the nonabrasivesurfaces of said spaced apart regions so that said active area does notproject above the nonabrasive surface of said safe area, each saiddepression of said active area having a size such that said workpiecewill not fit therein but in which the raised portions of the workpiecewill fit therein, said active area having a mechanism formed therein forabrading the raised portions of the workpiece that project into theactive area, whereby when the raised portions of the workpiece areabraded, the safe area of said working area is then caused to engagesaid workpiece and further abrasion of the workpiece does not occur. 2.The tool of claim 1, wherein said depressions are formed with a sizeselected so at least a portion of said raised portions can enter intosaid depressions.
 3. The tool of claim 1, wherein said active areacomprises said depressions coated with an abrasive material.
 4. The toolof claim 1, wherein said active area comprises a sharp edge formedwithin said depression.
 5. The tool of claim 1, wherein said activeabrading areas of said tool comprise one or more grooves.
 6. The tool ofclaim 5, wherein each said groove has a depth that is a function of theheight of the raised portions of the workpiece.
 7. The tool of claim 1,wherein each said depression comprises a trough portion and a roundededge joining said trough portion to said safe area, at least a portionof said trough portion being lined with an abrasive grit.
 8. The tool ofclaim 1, wherein each said depression comprises a trough portion and arounded edge joining said trough portion to said safe area, and furtherincluding a sharp abrading edge formed within said trough portion. 9.The tool of claim 1, wherein said depressions are formed as a pluralityof grooves, each said groove extending axially along a shank portion ofsaid tool, and each said groove spaced annularly from an adjacent groovearound the shank portion of said tool.
 10. The tool of claim 1, whereinsaid tool is constructed of a tubular member having one or moreopenings, each opening defined by a hole formed through a sidewall ofsaid tubular member, said tubular member having an inner surface and anouter surface, and each said opening including a peripheral edge, and aninside edge is formed where said peripheral edge joins said innersurface, and an outside edge is formed where said peripheral edge joinssaid outer surface of said tubular member, and wherein said active areacomprises a sharp portion of said inside edge.
 11. The tool of claim 10,wherein said outside edge is structured so as to be nonabrasive.
 12. Thetool of claim 1, wherein said tool is structured to remove the raisedportions of the workpiece without rotation of said tool.
 13. The tool ofclaim 1, wherein the depression is constructed with a depth such thatthe mechanism for abrading the raised portions causes substantiallycomplete removal of said raised portions from the workpiece.
 14. Amethod of engaging an ultrasonic tip with a tooth surface to remove atleast a portion of accretions from the tooth surface without damagingthe surface of the tooth, comprising the steps of: using said ultrasonictip having a working area including a safe nonabrasive area and anactive abrasive area, said active abrasive area defined by at least onedepression structured for abrading material, said depression surroundedby said safe nonabrasive area; engaging the working area of saidultrasonic tip with the section of the tooth surface having saidaccretions; moving the working area of said ultrasonic tip in contactwith the tooth surface so that the accretions of the tooth surfaceproject into said active abrasive area and at least a portion of theaccretions are removed; continuing movement of the working area of saidultrasonic tip on the tooth surface to remove portions of theaccretions; and wherein after at least a portion of the accretions areremoved from the tooth surface by the active abrasive area of saidultrasonic tip, said safe nonabrasive area that surrounds said activeabrasive area prevents abrasion of the tooth surface even while theworking area of said ultrasonic tip engages the surfaces of the tooth.15. The method of claim 12, further including the step of removing atleast a portion of accretions of material from a tooth root in alocation not visible by a user of the ultrasonic tip, and withoutdamaging portions of the tooth surface.
 16. The method of claim 12,further including the step of engaging the ultrasonic tip with the toothsurface to reduce the roughness of accretions therefrom without concernof removing portions of the tooth surface.
 17. The method of claim 14,further including removing portions of the accretions of the toothsurface without rotation of said ultrasonic tip.
 18. The method of claim14, further including reducing the height of the accretions until theabraded tooth surface is substantially smooth.
 19. A tool for reducing aroughness of accretions from a tooth surface, said accretions defined byraised portions on the tooth surface,said tool comprising: an elongatedtip formed of a rigid metal and of a size suitable for ultrasonicvibrations; said elongate tip having a working area that includes asmooth surface and a depression formed in the smooth surface, the smoothsurface of said working area is not effective to damage the toothsurface; the depression of said working area being formed in said smoothsurface so that the smooth surface surrounds said depression; and anabrasive mechanism located in said depression and responsive to theultrasonic vibrations of said tool to reduce the roughness of the raisedportions of the accretions that project into said depression, whereinafter the roughness of the raised portions of the accretions is reducedby the abrasive mechanism of said working area, the smooth surface thatsurrounds said depression engages the tooth surface and prevents furtherabrasion of the tooth surface, even while the working area of said toolengages the surface of the tooth.
 20. The tool of claim 19, wherein saidabrasive mechanism comprises a grit bonded to a surface of saiddepression.
 21. The tool of claim 19, wherein said abrasive mechanismcomprises a sharp edge formed in said depression.
 22. The tool of claim19, wherein said tool is structured to reduce the roughness of theraised portions of the accretions without rotation of said tool.
 23. Thetool of claim 19, wherein the depression is constructed with a depthsuch that the abrasive mechanism causes substantially complete removalof said raised portions from the workpiece.